There are millions of modern multi-speed bicycles in use in the United States and many more millions are being manufactured and sold each year in addition to many imported multi-speed bicycles. In many of these multi-speed bicycles, the speed ratio or gear ratio between the driving (front) sprocket which is turned by the foot pedal cranks and the driven (rear) sprocket at the rear wheel is changed by derailing the sprocket chain to shift it between sprockets of various sizes. For example, in the so-called "ten speed" bicycles which are very popular at the present time, there are two front sprockets and five rear sprockets. The chain can be derailed and shifted by respective hand-lever operated derailer mechanisms positioned near the front and rear sprockets to provide a driving relationship between either of the front sprockets and any one of the five rear sprockets, thus achieving ten different gear ratios, as may be desired by the rider for traversing various inclines or level stretches of roadway at various speeds. There are also five-speed bicycles in which a single front sprocket is used with five rear sprockets. A single derailer mechanism is associated with the multiple rear sprockets for shifting the chain onto the respective rear sprockets to provide the five different driving ratios. These ten speed, five speed and similar multi-speed bicycles are referred to herein as the "chain derailer" type.
In addition, there are many multi-speed bicycles in which a gear shifting mechanism is included within the hub of the rear wheel, for example, to provide three different driving ratios. The rear hub gear shifting bicycles are referred to herein as the multi-speed "gear shifter" type.
Since the invention and development of such modern bicycles, the advantages of back-pedal braking have been recognized. Much work has been done on back-pedal brake systems and much prior art exists. Yet today in the marketplace in the United States, no practical system for back-pedal braking of the popular multi-speed "chain derailer" type bicycle exists. Hand-operated braking systems must be used.
Before the advent of multi-speed bikes, the "coaster" brake was the most popular type of bicycle brake. The "coaster" brake mechanism was housed in the rear hub, and brake operation was obtained by reversing the pedals, thereby tensioning the bottom of the chain, which applied reverse torque to the rear sprocket for applying the brake.
The three-speed bicycle involved a gear mechanism located within the hub of the rear wheel as mentioned above. When attempts were made to include a "coaster" brake within the rear hub, together with the gear shifter mechanism, the rear hub became quite large, bulky and complex, causing severe disadvantages from a practical viewpoint. Thus, as a practical matter, in the marketplace in the United States, hand-operated braking systems are also used with multi-speed gear shifter type bicycles.
In these various multi-speed chain derailer and gear shifter bicycles, as now existing in the U.S. marketplace, the brake mechanisms for the front and rear wheels are actuated by respective hand-operated levers positioned on the handle bar near the handle grips. There are a number of serious disadvantages or safety hazards inherent in these hand-operated lever braking systems, as now existing in the marketplace, as follows:
1. The rider must partially release his hold on the handle grip in order to extend his fingers to reach and grasp and squeeze the brake lever. If the bicycle is negotiating a bumpy, pebbled or slippery surface, the momentary release of the handle grips can cause loss of steering control. PA1 2. A substantial hand span or finger extension is required to reach the brake-actuating levers. If the rider is a young person or an adult with small hands, it is quite difficult for the rider to reach the brake lever while adequately holding onto and controlling the handle bar grip. PA1 3. The front and rear brake mechanism are controlled by separate levers, which arrangement presents hazards when riding down hill or at substantial speed. If the rear brake mechanism fails, or if the rider squeezes too hard on the lever for the front brake, the front wheel may suddenly stop, thereby flipping the bicycle and catapulting the rider head-first over the front wheel. PA1 4. On different bicycles the hand levers are located in different places and at different distances (spans) from the hand grips, depending on the orientation and placement of their mounting clamps on the handle bars. When a rider is using a borrowed or a rented bicycle in which the brake levers are located differently from those on a familiar bicycle, there is an awkward or hazardous delay in applying the brakes while the rider's fingers are nervously searching out the location of the brake levers. Alternatively, the rider may avert his eyes from the path ahead in an emergency to look down to find the levers. This diversion of vision is undesirable and can be very dangerous when automotive traffic is near. PA1 5. When the hand brakes are suddenly applied in an emergency stop, the bicycle may start to skid or lean over. The human reflex action is often to tighten the grip, which jams the brakes and worsens the incipient skid. PA1 6. When using the racing style handle bar with the underslung U-shaped hand grip, most riders cruise with their hands on the straight horizontal central portions of the handle bar, because this central portion is higher, thereby enabling the rider to sit up straighter. The brake levers are often mounted down near the underslung hand grips. Thus, the rider must release both hands and completely shift both hands down to new positions in order to reach the brake levers. In some cases, auxiliary levers are installed so that the rider can reach this auxiliary lever with the hands remaining in the cruising position. These auxiliary levers increase the complexity and expense. In addition, they are not available on many modern bicycles, leading to such hazards as described under paragraph No. 4 above, when the rider has become accustomed to using them on a familiar bicycle. On camping trips, some riders cannot carry all of the desired gear on their back or on a carrier over the rear wheel. Some equipment then ends up strapped to the handle bar, in which case the auxiliary lever can become accidentally jammed, preventing the brake from being applied by use of the regular lever. PA1 7. Also, there are times when a bicycle rider may wish to reach out to ward off an impact, and at such an instant, the rider is forced to abandon any chance of using the hand-brake lever on the respective side where the arm is being extended. It may be the rear brake which is abandoned, leaving only the front brake, which can veer the bicycle off from the rider's intended track. PA1 8. Observation of hundreds of multi-speed bicycle riders has revealed that in the majority of cases, the rider's hands are not on the brake levers most of the time. This means a greater elapsed time between the decision that a stop should be made and the movement when the hands reach and grasp the levers for applying braking action. In contrast, in the majority of cases for most of the time, the rider's feet are resting on the pedals so that a lesser elapsed time occurs between the decision to stop and the movement when braking action is applied by back-pedal action. PA1 9. The hands are busy performing many functions: steering, shifting, helping to maintain body balance, giving hand signals, sometimes holding a package, or warding off bushes or twigs, in general, very busy. Whereas, the feet have only one function to perform. This invention relieves the hands of one major activity and assigns it to the feet. PA1 10. In the average person, the leg muscles are more powerful than the hand-span and, therefore, are more suited for applying the braking action.
Thus, as pointed out above, there are serious disadvantages or safety hazards involved with hand-operated lever braking systems for multi-speed chain derailer or gear shifter bicycles. These disadvantages and hazards are augmented in the case of children whose hands are weaker and who often ride their bicycles at top speed with exhuberance under conditions where an adult would proceed cautiously, the children tending to rely on their ability to brake suddenly at the last instant.
The factor which does not allow the application of the "coaster" brake to the "chain-derailer" type bicycles is the fact that the chain cannot apply a reverse load (reverse torque) to the rear sprocket because of the slack which must be provided in the chain arrangement and the spring-biased take-up jockey wheel or equivalent slack take-up mechanism associated with the bottom portion of the chain.
In addition, the "coaster" brake, being actuated by the chain, could only operate the rear wheel brake which also is a disadvantage wherever two-wheel braking is desired as being more efficient.